docs: def verify2(self):
          """Last verification step.
  
          The derived keys (output, input) are returned here.
          """
          output_key = hkdf_expand('MediaRemote-Salt',
                                   'MediaRemote-Write-Encryption-Key',
                                   self._shared)
  
          input_key = hkdf_expand('MediaRemote-Salt',
                                  'MediaRemote-Read-Encryption-Key',
                                  self._shared)
  
          log_binary(_LOGGER, 'Keys', Output=output_key, Input=input_key)
          return output_key, input_key